JPH06503246A - Vascular catheter with low profile distal end - Google Patents

Abstract

An ultrasonic imaging catheter comprises a catheter body having a distal region and proximal region. The distal region has a reduced cross-sectional area compared to that of the proximal region, and the proximal region includes at least two lumens therethrough for accommodating a movable guidewire and a rotatable working element, respectively. The catheter body may be inserted over the moveable guidewire, with the guidewire passing through a lumen in the distal region and the guidewire lumen in the proximal region. After positioning the catheter body, the guidewire can be retracted from the distal region and into the proximal region, leaving the lumen in the distal region available for the rotatable working element. Such a construction allows over-the-wire imaging of the catheter while minimizing the width of the catheter in the distal region which remains available for placement of the working element.

Description

[Detailed description of the invention] TECHNICAL FIELD This invention relates generally to the construction and use of vascular catheters, and more particularly to the construction and use of vascular catheters. Reduced dimension distal tip capable of selectively accepting a wire or actuating element Relating to a vascular catheter having an end.

Arteriosclerosis, also known as atherosclerosis, is the formation of atherosclerosis or plaques on the walls of blood vessels. It is a common human disease caused by the deposition of fatty substances called plaques.

These deposits can be found in peripheral blood vessels that supply the body's limbs and in the coronary blood vessels that supply the heart. It happens to both. When deposits build up in localized areas of blood vessels, they can restrict blood flow. A person's health is in serious danger.

vasculature, where a balloon-tipped catheter is used to widen narrowed areas within the blood vessel Attempts such as shaping, cutting away the stenosis using blades or other cutting elements Loam incision, in which laser energy is used to remove at least part of the stenosis. treatments to reduce or remove such vascular deposits, including laser angioplasty. Many solutions have been proposed.

To apply such interventional techniques more effectively, various vascular imaging devices are available. and methods have been used. Of particular interest to the present invention, at the distal end Imaging the stenotic area from within the blood vessel using a lumen portrait catheter containing an ultrasound transducer was occurring.

Many specific designs for such ultrasound imaging catheters have been proposed. Ta. One solution is to use a phased ultrasound imaging transducer at the tip of the vascular catheter. was to use an array. Such solutions require mechanical manipulation of the transducer It is advantageous in that it does not The problem is that statue tributes are restricted. like this A phased array vascular imaging catheter is available as the Katascanner I system. Commercially available from EndoSoex, Inc. (Runph Cordova, California). Ru.

A more promising solution for vascular ultrasound imaging is to mechanically rotate the transducer itself. or by incorporating a mirror that radially reflects the ultrasound signal from the transducer. By mechanically rotating the ultrasonic signal, Ru. Such mechanical rotation generally provides better imaging than the use of phased array devices. quality, but the design of the catheter does not allow the passage of the transducer and/or associated mirror. It must be possible to rotate at speeds in the range of 500 to 2000 rpm. It's a problem because it doesn't exist. Moreover, if it comes into contact with blood vessels, it can cause considerable damage. Internal blood vessels must be protected from rotating parts that cause

A number of specific designs for ultrasound imaging catheters have been described. early The design is shown in U.S. Pat. No. 4.794.931, in which the imaging The mechanical components of the device are positioned within the housing at the distal end of the catheter. It is. This housing is used to position the catheter within the vascular system. It has a fixed guidewire at its distal end. Fixed guide wire such as Although excellent image quality can be obtained by using An “over-the-wire” system where the tether can be introduced onto a separate (movable) guide wire. ” design is preferred. The use of a movable guidewire is recommended for bifurcation coronary arteries and Improved maneuverability and ease of catheter exchange, e.g. several methods, including facilitating replacement of the intervening catheter after imaging is complete. It has the following advantages.

A specific design for an "over the wire" ultrasound imaging catheter is shown in Figure 1. Ru. The catheter has an external catheter lumen 12 attached near its distal end. It has a tellbody 10. The distal end of the drive member 16 includes a rotatable ultrasonic An imaging assembly 14 is provided and the apparatus is mounted on a conventional movable guide as shown. It can be introduced onto the wire 18. However, this method using parallel lumen This design allows the width of the distal tip in the region of the ultrasound imaging element to It is a disadvantage because it must also be sufficient to accept. Ideally, very The imaging element to be rotated and this in the area of the imaging element, including only the catheter skin surrounding the imaging element. Catheter diameter should be minimized. Requires separate guidewire lumen By increasing this minimum size, this design is suitable for small vessel type defects. unsuitable for the affected area and unsuitable for passage through conventional guiding catheters. Ru.

The type of design shown in Figure 1 was manufactured by Meditech, Inc. ) is commercially available from. Pending application 3fE 07 with a design similar to the design in Figure 1 No. 422°935, the disclosure of which is incorporated herein by reference. Ru.

Another design for mechanical ultrasound imaging catheters is to replace the mechanical imaging components with conventional Parallel guidewire lumen by addressing the guidewire and replacing it avoid the need for As shown in Figure 2, such a catheter has a A single drive wire 22 capable of receiving a drive wire 22 supporting a sonic imaging assembly 24 A lumen catheter outer skin 20 is provided. This catheter outer skin 20 was originally Introduce it onto the guide wire. The guidewire is then completely removed and placed in the imaging assembly. It can be replaced with a solid. It is better to minimize the diameter of catheter 20. , always remove the guidewire and imaging section when attempting to reposition the catheter. It is necessary to replace the item, which is time consuming and disadvantageous. like this The catheter is commercially available from Intertrabi, Inc. (Costa Mesa, Calif.). ing.

For these reasons, a narrow profile in the area of the imaging part and a separate movable guide wall are required. It is possible to provide an ultrasound imaging catheter that can be introduced over the ear. desirable. Such a design eliminates the need to remove the guidewire from the catheter body. especially if you are considering imaging within the narrow distal region of the catheter without desirable. In particular, such imaging catheters more preferably exhibit a width of less than about 5 French to facilitate entry into the obstruction. is less than about 3 French.

Summary of the invention According to the invention, a vascular catheter has a proximal end and a distal end. It has a body. The catheter body extends proximally from its distal tip. at least one distal region extending in a proximal direction from a proximal end of the distal region; It has a proximal region that extends. Distal region has reduced cross-sectional area compared to proximal region with the distal region typically having only one lumen and the proximal region typically having only one lumen. The zone has at least one pair of parallel lumens.

The lumen in the distal region of the catheter body has both parallel lumens in the proximal region. Continuous. thus reciprocally disposed within one of the lumens of the proximal end. Selectively advance the driven shaft into the distal region and retract it back into the proximal region. be able to. passing the guidewire through the lumen in the distal region and the other lumen in the proximal region; That is, by placing the catheter in the lumen that is not occupied by the drive shaft. The body can be inserted over the guide wire. The distal end of the drive shaft has an actuating An element, typically an ultrasonic transducer, is provided to reciprocate the drive shaft. The ultrasound transducer can be moved in and out of the distal region by .

During use, the catheter is placed over a movable guidewire that is prepositioned at the desired location within the vasculature. You can do this by introducing a tell body. The distal region is the location of interest, typically the stenosis Manipulate the catheter body until located at the lesion. Catheter body in place Once the movable guidewire is in the distal region, retract it from the lumen, but not in the proximal retract (i.e., pull proximally) so that it remains within the lumen in the ). An actuating element on the drive shaft, typically an ultrasound transducer, is then placed in the distal region. advance distally into the lumen. The actuating element is then used to form the image. or other interventional technique and, upon completion, withdraw the actuating element into its lumen in the proximal region. I can put it in. The guidewire is then advanced through the distal region until the distal region is of interest. Place the catheter body back on the guidewire so that it can be moved to another position. Position.

Thus, the present invention provides a method for facilitating entry into coronary arteries and very tight stenotic lesions. In order for the distal region to have the smallest cross-sectional area and to be introduced onto a movable guidewire, Ability to hold the guidewire in place during imaging or other interventional procedures We provide an intravascular catheter that combines

Brief description of the drawing FIG. 1 shows a first catheter of the prior art.

FIG. 2 shows a second catheter of the prior art.

FIG. 3 depicts a catheter constructed in accordance with the principles of the present invention.

Figure 4 shows the catheter of Figure 3 with the actuating element advanced into the distal region; FIG. 3 is an enlarged view of the distal end.

FIG. 5 is a cross-sectional view taken along line 5--5 of FIG.

FIG. 6 is a cross-sectional view taken along line 6--6 of FIG.

FIG. 7 shows another configuration of the catheter of the present invention.

FIG. 8 is a cross-sectional view taken along line 8--8 of FIG.

FIG. 9 is a cross-sectional view taken along line 9--9 of FIG.

FIGS. 10 to 12 are similar to those shown in FIGS. 1 to 6 for imaging the stenosis defect. 1 illustrates a method of the invention using a catheter.

DESCRIPTION OF THE PREFERRED EMBODIMENT A catheter constructed in accordance with the principles of the present invention has a proximal end and a distal end. It has a long catheter body. This catheter body has at least two The distal region extends from the distal end of the catheter body to near the tip. the proximal region extends to positions spaced apart in the distal region, and the proximal region extends to the proximal end of the distal region. extending proximally from. The distal region has a common lumen extending through it and a coronal Has a reduced cross-sectional area to facilitate entry into blood vessels and/or tight stenotic lesions. are doing. The proximal end is adapted to receive at least two lumens extending therethrough. The first lumen has a somewhat larger cross-sectional area for conventional movable guidewires. and the second lumen is capable of receiving an actuator attached to the distal end of the drive shaft. It is possible to accept dynamic elements. Both the pedicle 1 and the second lumen are located in the distal region. open into a common lumen. Thus, the guidewire is inserted into the common lumen at the distal end and introducing the catheter body into the blood vessel through the first lumen in the proximal region; Can be done. After the catheter body is in place, insert the movable guidewire into the distal region. retracting into the first lumen and advancing the actuating element from the second lumen in the proximal region into the common lumen. advance. Thus, the cross-sectional area of the distal region is It is minimized because it is not necessary to accept both at the same time.

The catheter design of the present invention is an ultrasonic imaging probe used for vascular portraiture of blood vessels. It is expected that its greatest use will be found in the composition of Teter. In such a case, The actuating element has an ultrasound transducer with a focal length, which ultrasound transducer operating at a frequency suitable for imaging within the dimensions of . Ultrasonic transducer if required may be provided in an assembly together with a reflective material (mirror), in which , the ultrasonic transducer essentially emits ultrasonic energy in the axial direction and receives it in the axial direction. and the mirrors are oriented to reflect the emitted and received energy radially. ing. By using mirrors to reflect ultrasonic energy, The effective focal length over which the converter operates is increased to improve image quality. Reflective elements and transformations The space between the vessels eliminates the ring-down J effect, thus improving image quality. . The design and application of ultrasonic imaging transducers are described in U.S. Pat. No. 3.938.502, no. 4.576, 177 and 4.794.931, and these patent disclosure is incorporated herein by reference.

In addition to ultrasonic transducers, the present invention can be used for a wide variety of other actuating elements, especially rotatable actuators. Dynamic elements, such as cutters, polishers, rotating mirrors for reflecting the laser beam, etc. Suitable for configuration of vascular catheters that support Calculation using such actuating elements Tetel is a U.S. Patent No. 4.648.402, U.S. Pat. No. 4.631.052, the disclosures of which are hereby incorporated by reference. be incorporated into. The present invention provides a catheter outer sheath to protect the blood vessel lining. The catheter has a rotatable element that requires placement partially or completely within the catheter. Whenever you use it, you can find a use for it.

The catheter body has a single axial lumen defined in more detail below. or more flexible tubular members. Catheter body is a medical community to be inserted and manipulated within the patient's vasculature using techniques currently well known in suitable to bring the distal region of the catheter body to the desired location within the vasculature. be able to.

The overall dimensions of the catheter are determined by the application and vary widely in length, typically approximately between 40 cm and 150 cm, typically around 4 cm for peripheral catheters. between 0 cm and 120 a++, and approximately 11 cm for coronary catheters. It is between 0 cm and 150 CI. The diameter of the catheter body can also vary widely and The diameter of the proximal region is approximately between 2F (French) and 3F, and the diameter of the proximal region is representative. Generally, it is between about 3F and 6F. Particular advantages of the catheter of the present invention include the distal region. Ultrasonic waves have been made very small, and the lower limit of magnitude is typically achieved. Based on the diameter of the transducer or other actuating element. The size of such actuating elements The catheter body of the present invention will be further reduced with advances in the art. It is expected that the diameter of the pipe can be further reduced.

Catheter bodies can be constructed from a variety of biologically compatible materials, typically Includes silicone rubber, natural rubber, polyvinyl chloride, polyurethane, polyester natural materials such as polyethylene, polytetrafluoroethylene (PTFE), etc. is made from synthetic polymers. Catheter bodies are often strong, flexible Composite with reinforcement mixed within the elastic body to increase strength and toughness It is formed by Suitable reinforcing layers include wire mesh layers. catheter body Flexible tubular members are typically formed by extrusion and include one or more integral parts. A cavity is provided. In this case, the cathedral is removed by thermal expansion and contraction using conventional techniques. You can change the diameter of the metal. Specifics for forming the vascular catheter of the present invention The technology is well described in the patent and medical literature.

The catheter body consists of a single tube that extends the entire distance from the proximal end to the distal end. May be formed from tubular members or joined together in tandem or parallel The tubular member may be formed from two or more tubular members. from a single tubular member In the formed catheter body, the proximal region is expanded relative to the distal region, and both regions are form a suitable lumen inside. As a modification, a single tubular with a single lumen The member may form a distal region of the catheter body, the member having at least two axial A proximal region is formed from a second tubular member having an endoluminal lumen. In this case, a common lumen or and both regions such that the distal tubular member is continuous with both parallel axial lumens and the proximal region. It is better to join them together. As a second modification, the catheter body is located at the distal end. A single tubular section with a single axial lumen extending the entire length from the proximal end to the proximal end. It may have material. The proximal portion has a second tubular lug attached to the side of the first tubular lug, and each lumen is continuous through the first tubular member. catheter The distal region of the tell is the portion that remains in front of where the two tubes join.

The distal region of the catheter typically ranges from about 1cs+ to 2C11, more typically typically has a length in the range of about 2CI-10CII, with the proximal region extending from the distal region to the proximal region. It extends in the direction. However, the proximal region is the proximal end of the catheter body. It is not necessary to extend the entire distance. Guidewire often formed by the proximal region The lumen extends only a fraction of the distance from the distal region toward the proximal end of the catheter body. Preferably, it extends vertically, typically about IQcffl to 30 cm. Externally, it is preferable to extend from 15 Cffl to 25 c+s. In this way, Guy The lumen of the guide wire facilitates changing over the guide wire in the catheter. It is better to have a "single rail" design. Such a single-rail design is described in U.S. Patent No. 4.7. No. 48.982, the disclosure of which is incorporated herein by reference. It will be done.

The width of the distal region is typically less than about 0.15 cm, and usually about 0.13 cm. often less than about 0.1 cm. The width of the proximal region is typically , greater than about 0.17 cm, and often greater than about 0.2 cm. Of course, this width may not be uniform along the length of the catheter, some variation is allowed. .

The drive shaft, reciprocably disposed within the lumen in the proximal region of the catheter, is flexible and transmits torque from the proximal end of the catheter to the actuating element at its distal end. suitable for. Depending on the application, the drive shaft may be a solid core wire, but more Typically, it has a knitted configuration. A suitable drive shaft is available in pending application iK07150. No. 0.818, the disclosure of which is incorporated herein by reference.

In the case of ultrasonic transducers as actuating elements, the drive shaft is the necessary Support electrical leads.

The catheter according to the present invention has 11 cavities formed at the proximal end of the catheter body. It has a This housing is located inside the catheter body that supports the drive shaft. A means for sealing the lumen and for axially reciprocating the drive shaft within the catheter body. has been established. For ultrasound imaging catheters, the housing also the necessary electrical connections for connecting the electrical leads to the associated electronic imaging equipment. have. Additionally, the drive shaft rotates the ultrasonic transducer or other actuating element. and a spindle or other means for connection to an electric drive motor. suitable A suitable spindle and drive motor is described in U.S. Pat. No. 4,771,774. , the disclosure of which is incorporated herein by reference.

Referring to FIG. 3, a first embodiment 50 of the catheter of the present invention is shown.

The catheter 50 is a flexible catheter having a distal region 54 and a proximal region 56. It has a body 52. Distal region 54 extends from distal boat 60 to transition region 62 It has a single lumen 58 extending therethrough. Proximal region 56 includes first lumen 64 and second lumen. It has 66. The first lumen 64 supports a movable guidewire 68, which A guidewire 68 is passed from the proximal boat 70 through the lumen 58 and into the distal region as shown. It extends within the area and exits from the distal boat 60. In this way, the catheter 50 can be inserted over guidewire 68 in a conventional manner. within the second lumen 66 A drive shaft 72 is arranged so as to be able to reciprocate. As shown in Figure 3, the ultrasound image A forming assembly 74 is secured to the distal end of the drive shaft 72 and is attached to the guidewire. 68 extends into the lumen 58 of the distal region 54 and remains within the proximal region 56. Ru. However, as shown in FIG. When loaded, the ultrasound imaging assembly 74 is moved axially forward into the lumen 58 of the distal region 54. can be advanced.

In a preferred embodiment, ultrasound imaging assembly 74 emits ultrasound energy axially forward. an ultrasonic transducer 76 (FIG. 4) oriented to emit ultrasonic waves from the transducer 76; and a mirror 78 arranged to reflect sound wave energy generally in a radial direction. ing. When the drive shaft 72 is rotated, the ultrasonic transducer 76 and the mirror 78 generate ultrasonic waves. Both the sonic transducer 76 and the mirror 78 are mounted within the assembly 74 so that they rotate together. fixedly attached to each other.

Catheter 50 further includes a proximal bow secured to the proximal end of catheter body 52. 80. This proximal housing 80 is attached to the drive shaft 72. The lever 82 allows the user to control the ultrasound imaging assembly. 74 in its retracted position (as shown in Fig. 3) and in its extended position (as shown in Fig. 4). It can be selectively reciprocated between positions. Ultrasonic imaging assembly 74 is It is normally only used when in its extended shape. The catheter 50 is attached to a movable guide. retracting the ultrasound imaging assembly 74 when positioned over the wire 68; .

Additionally, housing 80 connects electrical leads on drive shaft 72 to generate ultrasound images. An electrical connector plug 84 for connecting to the necessary electrical equipment and a plug near the drive shaft 72. The spindle is provided at the end of the position and is connected to the motor drive device as described below. It has a total of $86. Therefore, (along or through the drive shaft 72) Connect electrical leads (not shown) from transducer 76 (extending from A ring and commutator (not shown) may be provided for the connection.

Referring to FIGS. 7-9, another embodiment 100 of the catheter of the present invention is shown. has been done. The catheter 100 is proximate to the distal region 104 of the catheter body. The first flexible tubular member 102 extends to a position region (not shown).

This first flexible tubular tube extends the entire length of the catheter body and has a distal port. It defines a single lumen 106 terminating in 108 . Near the catheter 100 The positioning region 11O is a second flexible tubular member attached to the side of the first flexible tubular member 102. The second flexible tubular material 112 has a port 114. It is connected to the lumen 106 of the first flexible tubular tube 102 via the tube. catheter 10 The distal region 120 of the first flexible tubular member 1 in the distal direction of the connecting port 114 It is configured as a 02 area. The lumen 122 of the second flexible tubular member 112 is The first The lumen 106 of the flexible tubular sleeve 102 has an ultrasound imaging assembly 134 at its distal end. The drive shaft 132 is received. As shown in FIG. 4 is located within the distal region 120 of the catheter 100. Of course, the image forming group Retract the body 134 behind the port 114 and into the proximal region 110 of the catheter. can be done. In this way, the lumen 106 of the distal region 120 is connected to the catheter lOO receptive to advancement of guidewire 130 for positioning or repositioning of It is.

Referring to FIGS. 10 to 12, insert the catheter into the stenosis region S in the blood vessel BV. 3 illustrates the use of the catheter 50 and guidewire 58 of FIG. 3 in positioning. do. Initially, the distal end is positioned beyond the stenosis region as shown in Figure 1O. Next, a guidewire 68 is introduced into the blood vessel in a conventional manner. Position the guide wire 68 Once determined, thread the proximal end of guidewire 60 through distal port 60 and then passing the wire through the lumen 58 of the distal region 54 and the lumen 64 of the proximal region 56. The catheter 50 is then introduced over the guidewire. Proximal region 54 is within the stenosis region Advance the catheter axially forward within the vessel until located. catheter 50 11, the ultrasound imaging assembly 74 is advanced to the position shown in FIG. Ru. (As a modification, while introducing the catheter into the blood vessel, the ultrasound imaging assembly 7 4 may be advanced to such position). Imaging assembly 74 is attached to the distal end of lumen 66. After proximate positioning, the guidewire 68 is inserted into the distal region until it exits the lumen 58. and distally until it is located entirely within lumen 64 within proximal region 56. I can put it in. Once guidewire 68 is removed from lumen 58, ultrasound imaging assembly 74 is removed. The ultrasound beam is advanced axially forward into lumen 58 where it is imaged in a conventional manner. An imaging assembly 74 can be used.

At any time during the imaging procedure, drive shaft 72 is retracted away from lumen 58. You can can be used to position catheter 50 after leaving the lumen. The guidewire can then be advanced axially forward again to allow it to move forward. Change example and to leave the guidewire 68 in place and introduce a different catheter. Catheter 50 may be retracted over the guidewire so that it remains in place for .

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Claims (15)

[Claims] 1. The catheter includes a catheter body having a proximal end and a distal end. The body has a proximal region with at least two lumens and a cross-sectional area of this proximal region. a distal region with a small cross-sectional area, and a distal end and a proximal end. , a drive shaft reciprocatably disposed in one of the lumens of the catheter body; an actuating element secured to the distal end of the drive shaft, thereby causing the drive cable to Selective reciprocation extends the actuating element into the distal region or near the A blood vessel cap characterized by being able to be retracted into the position area. Teter. 2. The catheter includes a catheter body having a proximal end and a distal end. The body has a proximal region with at least two lumens and a cross-sectional area of this proximal region. a distal region with a small cross-sectional area, and a distal end and a proximal end. , a drive shaft reciprocably disposed in a first lumen of the lumens of the catheter body; , An ultrasound imaging transducer secured to the distal end of the drive shaft and the lumen of the catheter body. a guide wire slidably disposed in a second lumen of the guide wire; Thereby, the catheter body can be introduced into the blood vessel over the guidewire, Remove the guidewire from the proximal region of the catheter body. and imaging transducer can be exchanged within the distal region of the catheter body. A blood vessel imaging catheter device characterized by: 3. The ultrasound imaging transducer is placed in tandem with this and transmits the signal from the transducer. disposed within an assembly having a mirror oriented to reflect radially outwardly; The blood vessel imaging catheter device according to claim 2, characterized in that: 4. Mechanically connects the drive shaft to the motor drive device at the proximal end of the catheter body. and means for axially translating the drive shaft while rotating the drive shaft. The blood vessel imaging catheter according to claim 2, further comprising means for tell device. 5. The distal region has a width of less than about 0.15 cm and the proximal region has a width of less than about 0.1 cm. Blood vessel imaging according to claim 2, characterized in that it has a width greater than 5 cm. Catheter device. 6. The distal region has only one lumen formed in continuation with the two lumens in the proximal region. The blood vessel imaging catheter device according to claim 2, having a lumen of Place. 7. The distal region and the proximal region are formed from one tubular member, and the proximal region is Vascular imaging according to claim 2, characterized in that it is extended to a distal region. Catheter device. 8. The distal region and the proximal region are formed from separate tubular members joined together. The vascular imaging catheter device according to claim 2, characterized in that: 9. The catheter body has at least one lumen and a distal end of the catheter body. a first tubular member extending from a distal end to a proximal end and having at least one lumen; The second tubular member is fixed to the side of the first tubular member, and the two inner cavities are close to each other at junctions spaced proximally from the distal end of the catheter body. the distal region is located distally to the junction and the proximal region The blood vessel image shape according to claim 2, wherein is located proximal to the junction. catheter device. 10. the second tubular member extends all the way to the proximal end of the catheter body; The vascular imaging catheter device according to claim 9, characterized in that: 11. Insert the guidewire into the blood vessel to the area of interest and insert it into the distal region of the catheter. Introduce the catheter over the guide wire so that it is located within the area of interest; Retract the guidewire from the distal region of the catheter to the proximal region and remove the guidewire. the ultrasound imaging transducer from the proximal region of the catheter while the Advance into the distal region and use an ultrasound imaging transducer to image the region of interest. A method for forming an image of the inside of a blood vessel, characterized by causing the blood vessel to grow. 12. The region of interest is a stenotic region with a narrowed lumen. The method according to claim 11. 13. It is characterized by generating an image by mechanically rotating an ultrasonic transducer. 12. The method according to claim 11, comprising: 14. Mechanically rotating the mirror that reflects the signal from the ultrasound transducer 12. A method according to claim 11, characterized in that an image is thus generated. 15. Retract the ultrasound imaging transducer from the distal region to the proximal region and insert the guidewire Advance the catheter from the proximal region to the distal region and reposition the catheter over the guidewire. 12. The method of claim 11, further comprising: